E-Series (with utility versions like AA, artillery, TD, etc.) because the Germones need some love m8, but if "fantasy", "prototypes", and "advanced" vehicles are being added... consider the Panzer IV Ausf. L and K, Panther Ausf. F and Panther II, Panzer IX and X, the E-79, and anything from these links that catches your eye :

http://forum.worldoftanks.com/index.php?/topic/66025-amazing-tank-designs/
http://k-e93-3.deviantart.com/art/Panzer-X-516478504
http://sketchuppower.blogspot.com/search?updated-max=2012-12-15T05:20:00-08:00
http://orig06.deviantart.net/a4e8/f/2012/295/c/1/super_heavy_tank_design_by_darkheart1987-d5iktte.png

What tank or vehicle should I make next in MOWAS2? Let me know, and make sure to subscribe to my channel.